Page 239 - Journal451
P. 239

วารสารราชบััณฑิิตยสภา
                                          ปีีที่่� ๔๕ ฉบัับัที่่� ๑ มกราคม-เมษายน ๒๕๖๓
             ศาสตราจารย์์ ดร.มงคล เดชนครินทร์                                               227



               Abstract: Serial Data Exchange Between Microcontrollers Using only Two
                          Signal Wires
                          Professor Dr. Mongkol  Dejnakarintra
                          Fellow of the Academy of Science,
                          The Royal Society of Thailand
                                This article presents a method for serial data exchange between
                         the  8088  Microcontroller  Board  (master  board)  and  the  PIC16F627A

                         Microcontroller Board (slave board). The 8-bit data byte is sent one bit at
                         a time consecutively from the sending board. The eight bits are combined
                         at the receiving board to retrieve the original data byte. About hardware,
                         the two microcontroller boards use only two cross wires for sending/receiving
                         control signals and data, but do not use additional two cross wires to check/
                         show readiness for data exchange as has been done in the author’s previous
                         article. The software in this present article uses a sync pulse for the master

                         board and the slave board to interrupt each other. This sync pulse precedes
                         a control/data bit code and coordinates the sending and receiving of the
                         code without using additional signal wires. When compared with the serial
                         data exchange scheme that uses four signal wires in the author’s previous
                         article, the procedure in this article has an advantage, namely, reduction of
                         signal wires from four to only two wires, but has a disadvantage, namely,
                         reduction of data exchange speed to lower than 1/4 of that used in the
                         four signal wire scheme. From a test in which the two microcontroller
                         boards were placed not farther than one foot apart, it was found that the

                         data reaching the destination board were correctly received, being the same
                         as those having been sent from the source board.

                         Keywords: microcontroller, serial data, interrupt, integrated circuit, 8088,
                                   8255, 8259, PIC16F627A
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